Smoking relapse rates remain high, innovative strategies are needed to lower them, and technology may help. This developmental research will examine whether providing virtual (web-based) social support to smokers, through Twitter-enabled interactive peer texting, can help smokers quit and avoid relapses. Twitter is a free social networking and micro-blogging service, one of the most advanced and novel technologies available today that can provide social support to smokers, and it is the only service that provides free texting to groups. It is global and has many features that are associated with treatment success including interactive, multi-way, live messaging and mobile accessibility, because the messages go instantly to mobile phones and to the web. In Phase I, we will develop a treatment protocol for smoking cessation and relapse prevention that is based on Twitter-enabled interactive peer messaging (Aim 1). In a one-year protocol development study (N=40), we will form two 20-person virtual quit smoking groups of smokers intending to quit in the next 30 days and encourage the members to interactively text each other on mobile phones. All participants will receive 8 weeks of free nicotine patches and referral to the National Cancer Institute's (NCI) online Smokefree.gov Quit Guide;they will also be asked to select a quit date in the next 2 weeks to ensure everyone is facing similar cessation tasks and symptoms and thereby facilitate peer communication. The primary outcomes will be 7-day point prevalence abstinence at 7, 30 and 60 days following the quit date. An automated computer program will monitor each group's engagement by analyzing the number of Twitter messages exchanged by date and username, and will provide computer-generated feedback to the groups to optimize engagement. In this study, we will also test our methods for recruitment and screening, Twitter training, and assessments and refine our protocol as needed to ensure a viable Phase II trial. In Phase II, we will conduct a two-condition randomized controlled trial (Aim 2). Again, all participants (N=240) will receive 8 weeks of free nicotine patches and referral to the NCI's online Smokefree.gov Quit Guide, and will be asked to identify a quit date in the next 2 weeks. Randomization, at the individual level, will be to one of two conditions: (1) Twitter-enabled interactive peer messaging that consists of virtual quit-smoking groups that interactively text (protocol developed in Phase I), or (2) a control condition, which will not receive the Twitter intervention. There will be 6 quit-smoking Twitter support groups with 20 smokers randomly assigned to each group (N=120, plus 120 controls). The primary outcomes will be 7-day point prevalence abstinence at 7, 30 and 60 days following the quit date. This two phase research will provide pivotal pilot data and crucial information about the viability and methodology of a longer-term and broader scale randomized controlled trial. PUBLIC HEALTH RELEVANCE: Twitter-enabled Mobile Messaging for Smoking Relapse Prevention Narrative Relevance Many smoking cessation treatments exist but engagement remains low and relapse rates remain high, suggesting the need for more innovative, accessible and interactive treatment strategies. In two phases, we will develop, pilot and evaluate a novel, interactive, live treatment for providing peer-based social support to smokers who are trying to quit, via Twitter on mobile phones. Phase I will develop a treatment protocol for this novel treatment;Phase II will be a randomized controlled trial comparing this treatment to a base website intervention. Consistent with U.S. Clinical Guidelines, free nicotine patch will be provided. 1